I owned a house on a 1000 year lease. Didn't bother me. the ground rent was €6 a year. I owned it less than 10 years, and the ground rent was not collected, but if it was, it wasn't really a big deal.
You can buy out the lease, but the legal costs may not be worth it, if the lease is legally solid and the rent is low.
Lots of people of our parents generation have a problem with this, but this was a bit of landlord paranoia.
You should ask your solicitor to explain the details and get reassurance, but I wouldn't let it put me off a house purchase.